st: Repeated time values in panel in bootstrap routine

I'm running a bootstrap routine with household-level panel data and
am getting the Stata error message: "repeated time values within
panel - the most likely cause for this error is misspecifying the
cluster(), idcluster(), or group() option"

where -hhid- is the household-level identifier, and -myboot- is a
program that runs a probit regression and then computes the average
partial effect for several variables. I've run this bootstrap syntax
previously on household-level data from the same database (which used
the same household-level identifier) and did not have this problem,
thus I don't understand how I could have misspecified the cluster or
idcluster option. I've tried clustering at the village level
instead, but I get the same error message. I've also tried running
the syntax on only one year of the panel, and I still get the same
message. I'm wondering if anyone has any suggestions on what I might
be doing wrong.